1. Field of the Invention
This invention relates to methods of joining articles together with the aid of conductive polymer components, and to novel articles for use in such methods.
2. Prior Art
Conductive polymers are well known. They comprise a polymeric component and, dispersed or otherwise distributed therein, a particulate conductive filler, e.g. carbon black. Conductive polymers have been widely used in electrical heaters, including heaters which are in the form of heat-recoverable articles or which are secured to heat-recoverable articles so that, by powering the heater, the article can be caused to recover. Typically, the recovery of the article results in joining, repairing, reinforcing or otherwise modifying one or more substrates around or against which the article recovers. Recently, it has been shown that conductive polymers which retain substantial strength above their melting point, especially sintered polymers such as ultra high molecular weight polyethylene (UHMWPE), are particularly useful for modifying pipes composed of organic polymers (plastic pipes). Reference may be made for example to U.S. Pat. Nos. 3,987,276, 4,085,286, 4,177,376, 4,177,446, 4,421,582, 4,455,482, 4,570,055, 4,575,618, 4,686,071, U.K. Patent Nos. 1,265,194, 1,449,539, and 2,124,439, German Patent Application No. 3,442,674, U.S. patent application Ser. Nos. 596,761, now abandoned, published as European application No. 157,640, 582,105, now abandoned, published as European application No. 153,199, and 818,845, now abandoned, published as European application No. 231,068, and copending commonly assigned U.S. patent application Ser. Nos. 720,117 (MP0922) filed Apr. 2, 1985, 720,118 (MP1039) filed Apr. 2, 1985, 784,288 (MP1086) filed Oct. 4, 1985, 818,846 (MP1100) filed Jan. 14, 1986, 853,805 (KP1117) filed, Apr. 18, 1986, 867,830 (MP1130) filed May 27, 1986, 17,497 (MP1180) filed Feb. 23, 1987, 61,353 (MP1186) filed Jun. 11, 1987, 61,354 (MP1187) filed Jun. 11, 1987, 61,259 (MP1202) filed Jun. 11, 1987, 67,679 (MP922) filed Jun. 26, 1987, 75,929 (MP1095) filed Jul. 21, 1987, 89,389 (KP1130) filed Aug. 25, 1987, 120,883 (HP1231) filed Nov. 16, 1987, 132,698 (MP0907) filed Dec. 14, 1987, and 164,046 filed Mar. 4, 1988). The disclosures of each of the patents and patent applications referred to above are incorporated herein by reference.